1. Technical Field
The present disclosure relates to a starter to start an engine mounted on a vehicle, and more particularly to a starter provided with an electromagnetic solenoid unit integrating a function in which rush current is suppressed when the motor of the starter is activated.
2. Description of the Related Art
Recently, to reduce carbon dioxide emissions and enhance fuel efficiency, vehicles provided with an idle stop system (hereinafter referred to ISS) that automatically stops and restarts the engine have been increased. Since vehicles having ISS stop the engine every time when the vehicles have to stop at the intersection due to red traffic lights or due to a traffic jam and restart the engine in response to a restart request, the frequency of the engine start operation is significantly increased.
In this respect, a problem arises that a large amount of current (referred to as starting current or rush current) flows when the motor is activated in response to the engine restart request after the idle stop operation is performed. Specifically, when the large amount of current flows, the terminal voltage of the battery is greatly decreased so that instantaneous power failure occurs thereby causing momentary stop of the electric equipment such as meters, audio equipment or navigation system. Generally, since the vehicle provided with the ISS performs the idle stop on the road, a large amount of current flows every time when the starter operates so that the driver may be stressed significantly from this phenomena.
To avoid occurrence of the instantaneous power failure, suppression resistor is employed. For example, Japanese Patent Application Laid-Open Publication No. 2011-142067 discloses a technique in which an electromagnetic relay (referred to as ICR (In-rush current reduction) relay) that integrates a suppression resistor is connected to an activation circuit of the motor and a low resistive circuit path and a high resistive circuit path are controlled to be switched therebetween in response to the relay contact being ON and OFF. This ICR relay forms high resistive circuit path including the suppression resistor when the ICR relay is opened (turned OFF) in response to activation of the motor. As a result, suppressed current flows into the motor from the battery through the suppression resistor, whereby significant voltage drop at the terminal of the battery can be avoided. Subsequently, when the relay contact is closed (turned ON), both ends of the suppression resistor are short-circuited to form the low resistive circuit path, whereby the whole battery voltage is applied to the motor.
However, since the ICR relay conventionally used is an individual component, it is necessary to prepare a signal line in order to operate the ICR relay and a harness to connect the ICR relay and the starter, so that necessary man-hours and the number of components are increased, thereby increasing the system cost. Further, the ICR relay and the starter are connected by an additional harness whereby wiring resistance increases due to the additional harness. As a result, since the output power of the starter is decreased, depending on types of vehicles, it is necessary to use a starter having large enough output power compared to conventionally used starters.
Furthermore, since a fixing portion to fix the ICR relay is required to be disposed in the starter housing or other portion in the vehicle side, depending on types of vehicles, there is a difficulty to dispose the fixing portion in the vehicle. When the ICR relay is required to be disposed at battery side with respect to the B terminal (i.e., a bolt-shape connection terminal to which the harness is connected) of the electromagnetic switch, voltage is always applied to the connection terminal of the ICR relay which is connected to the activation circuit. Therefore, to avoid unnecessary short circuit caused by a foreign body or a tool contacting the connection terminal of the ICR relay, a protection cover is necessary to cover the connection terminal. As a result, necessary man-hours and the number of components are further increased so that the system cost will be increased.
The embodiment provides a starter provided with a small-size/light-weight electromagnetic solenoid unit that integrates a conventional ICR relay function (function capable of suppressing rush current).